The cellular stress response in yeast and metazoans is complex, encompassing precisely regulated signaling pathways that coordinate processes such as nutrient sensing and transcriptional/translational regulation. The S. cerevisiae kinase Ksp1 plays a central role in this process. KSP1 was first identified in a screen for high-copy suppressors of a mutation in the nucleotide exchange factor SRM1. More recently, we and others have identified KSP1 as a gene required for wild-type yeast pseudohyphal growth, likely through its association with the Target of Rapamycin Complex (TORC1). Ksp1 negatively regulates autophagy via TORC1, and its localization changes during pseudohyphal growth. In particular, we have found that Ksp1 kinase activity is required for the transition to a pseudohyphal growth form in competent strains of S. cerevisiae. The signaling network of Ksp1, however, has not been studied directly on a proteome-wide scale in a filamentous background. To address this, we undertook an analysis of Ksp1 signaling through quantitative phosphoproteomics, identifying proteins differentially phosphorylated in a catalytically inactive kinase-dead Ksp1 mutant under conditions of nitrogen and glucose stress. Gene Ontology term enrichment analysis of the set of proteins differentially phosphorylated upon loss of Ksp1 kinase activity identifies a statistically significant set of proteins associated with mRNA-protein (mRNP) granule formation. mRNPs, encompassing P-bodies and stress granules, present an additional form of stress response thought to regulate mRNA translation. We find that Ksp1 localizes to mRNP granules in a filamentous background, in agreement with recent studies of mRNPs in a non-filamentous yeast strain. Moreover, the kinase activity of Ksp1 is required for wild-type localization of several mRNP component proteins/regulators upon growth to a high cell density, including Pbp1 and the P21-activated kinase ortholog Ste20. We further find that Ksp1 kinase activity regulates the localization of Kog1, a subunit of TORC1. Collectively, these results suggest a function for Ksp1 in coordinating TORC1-signaling and the regulation of mRNP dynamics, likely through phosphorylation of key effectors. Ongoing studies are aimed at identifying the mechanism through which this signaling is coordinated.